Technical Field
The invention relates to an electric capacity measurement apparatus, and particularly relates to an electric capacity measurement apparatus with temperature compensation and a temperature compensation method thereof.
Related Art
By performing an integral (accumulation) operation on a current flowing into/out of a battery, a coulomb counter can be used to measure an electric capacity of the battery. Generally, settings of the coulomb counter have to be adjusted according to different applications, where one setting is an invalid current range, and another setting is a zero current offset.
Further, a main purpose of setting the invalid current range of the coulomb counter is to filter tiny noises measured by the coulomb counter around a zero current. In other words, when a current value measured by the coulomb counter is smaller than the invalid current range, the coulomb counter takes the current value as the zero current. If the coulomb counter cannot accurately filter such tiny noise, it may cause a measurement error after a long time accumulation.
On the other hand, a user can calibrate the coulomb counter according to the zero current offset of the coulomb counter to eliminate a deviation of current measurement. If the offset is not correctly set, the current measured by the coulomb counter may have a deviation amount. Similarly, after a long time measurement, the coulomb counter generates an error.
The above two settings are generally adjusted through one set of parameters according to different applications. However, under different environment temperatures, characteristics of the coulomb counter are accordingly changed. In other words, the invalid current range and the zero current offset of the coulomb counter are also changed along with temperature variation. If the invalid current range and the zero current offset of the coulomb counter cannot be dynamically adjusted along with the temperature variation, the coulomb counter may generate an error.